This invention relates generally to the allocation of liquids containing various chemical compositions or compounds to locations where assays may be performed to evaluate the chemical compositions, or where the compositions may be combined with other substances, such as other chemical compositions or reagents, prior to evaluation. In one particular aspect, the invention is concerned with the analysis of chemical compositions which have been released from solid supports upon which the compositions were previously synthesized.
Processes for synthesizing various chemical compositions or compounds on solid supports, such as beads, are well known. For example, such processes are described in copending U.S. application Ser. No. 08/149,675, filed Nov. 2, 1993 now U.S. Pat. No. 5,503,805 and Ser. No. 08/146,886, filed Nov. 2, 1993 now U.S. Pat. No. 5,639,603, the disclosures of which are herein incorporated by reference. After synthesis, it is often desirable to analyze the compounds synthesized on the beads. One such process is by placing the beads into a plurality of wells containing a liquid. A portion of the compound on the beads is then released into the liquid. Assays are then performed on the liquids containing the compounds to evaluate the compounds.
Before performing the assays, it is often desirable to separate the beads from the liquids containing the released compounds. One such method is by providing a plurality of wells having open bottom ends. A filter is placed near each open end, with the beads resting upon the filter. After the compounds have been released, a valve at each bottom end is opened so that the liquids may drain through the bottom ends, with the beads remaining on the filter.
Such a method for separating the liquids from the beads is undesirable for a variety of reasons. One particular drawback is that a significant amount of the liquid remains within the filter. This becomes particularly problematic as the volume of the wells becomes smaller, resulting in too little of the liquid being transferred from the wells. Another drawback is that such a method provides no convenient way for selectively removing only a portion of the liquid from the wells so that additional assays can be performed on the remaining liquids or so that the compounds can be combined with other compounds for further evaluation.
Hence, it would be desirable to provide systems and methods to efficiently remove all, or, in some cases, only a selected portion of the liquids from the wells so that assays may be performed on the liquids.
Another challenging aspect of evaluating compounds released from solid supports is the amount of time required to perform assays in order to evaluate a particular compound. For example, if each well contains only a single bead, separate assays must be performed on the liquid removed from each well. In some cases, throughput may be increased by placing a plurality of beads into a single well and releasing the compounds. Assays may then be performed on the liquids removed from the wells. For wells producing a positive result, each bead within the well must then again be tested to evaluate the compound. This usually employs synthesizing the same compounds on the beads, releasing the compounds, and again performing assays. Such a procedure is both burdensome and time consuming, particularly if thousands of beads are involved in the process.
Hence, it would be further desirable to provide systems and methods for evaluating various compounds in a more efficient manner. It would be particularly desirable if such systems and methods effectively reduced the amount of time required to evaluate a particular compound. It would be further desirable if such systems and methods provided versatility so that various compounds may be combined with other substances prior to evaluation of the compounds.